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Completed No phase listed Observational

Effect of Body Position on Spirometry in Abdominal Obesity.

ClinicalTrials.gov ID: NCT03347604

Public ClinicalTrials.gov record NCT03347604. Field values are reproduced from the official study page; the official ClinicalTrials.gov record remains the source of truth for eligibility, enrollment, and contact information.

ClinicalTrials.gov public records Last synced Sep 9, 2026, 1:48 AM EDT

Data is sourced from official ClinicalTrials.gov public API records. Always review the official ClinicalTrials.gov record for the latest information.

Brief summary

Reproduced verbatim from the official ClinicalTrials.gov record. Not medical advice.

Objective: Study the effect of body position on spirometry in obese patients as defined by waist to hip ratio (WHR) of greater than 0.85 in women, and 0.9 in men Background: Spirometry is routinely ordered to work up dyspnea in obesity. The most common abnormality is a restrictive disease pattern. The underlying mechanisms of this pattern are not completely understood. One plausible explanation is diaphragmatic weakness or skeletal muscle weakness. The change in forced vital capacity (FVC) from sitting to supine is a very sensitive and specific test for detecting diaphragmatic weakness. The effect of body position on spirometry in obesity has not been extensively studied, and there are no studies that look at this when obesity is measured by waist to hip ratio. Effect of body position has been studied in normal patients, and it is expected the FVC can decrease as much as 10% when changing from sitting to supine. The investigators do not know what would be considered 'the normal' amount for FVC to decrease by in the obese population, and thus would like to test patients with increased WHR both in sitting and supine position. The investigators also want to do muscle strength test by measuring the maximal inspiratory and expiratory pressures (MIPs and MEPs). Anticipated results: the investigators anticipate that our study population will replicate the restrictive disease pattern usually seen in obesity. The investigators also anticipate for the FVC to decrease when in the supine position compared to sitting. The amount by which it decreases will likely fall between 10 -25%. The investigators anticipate to not find any abnormalities in MIPs and MEPs in obesity.

Study identification

NCT ID
NCT03347604
Recruitment status
Completed
Study type
Observational
Phase
Not listed
Enrollment
30 participants

Conditions and interventions

Interventions

Diagnostic Test

Eligibility (public fields only)

Age range
18 Years and older
Sex
All
Healthy volunteers
Healthy volunteers not accepted

This page does not interpret eligibility. Detailed inclusion and exclusion criteria are on the official ClinicalTrials.gov record.

Study timeline

Start date
Oct 5, 2017
Primary completion
Aug 29, 2018
Completion
Dec 29, 2018
Last update posted
Jul 7, 2019

2017 – 2018

United States locations

U.S. sites
1
U.S. states
1
U.S. cities
1
Facility City State ZIP Site status
Rush University Medical Center Chicago Illinois 60612

Site contact phone numbers, emails, and investigator names are intentionally not displayed here. Open the official ClinicalTrials.gov record for site contact information.

About this trial record page

What this page shows
Public field values for ClinicalTrials.gov record NCT03347604, including study identification, conditions, interventions, eligibility (age, sex, healthy volunteer), timeline, and U.S. site list.
What this page does not do
No medical advice, eligibility judgments, treatment recommendations, study quality scoring, or AI-generated medical summaries. No site contact phone numbers, emails, or investigator names.
Where the data comes from
Sourced from the official ClinicalTrials.gov public API. The official record is the source of truth.
Last refresh
Last update posted Jul 7, 2019 · Synced Sep 9, 2026

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